Fine fiber media layer

Abstract

Disclosed are improved polymer materials. Also disclosed are fine fiber materials that can be made from the improved polymeric materials in the form of microfiber and nanofiber structures. The microfiber and nanofiber structures can be used in a variety of useful applications including the formation of filter materials.

We claim: 
     
       1. A filter media comprising:
 (1) a fine fiber layer, and 
 (2) a substrate layer; 
 the fine fiber layer comprising a fiber comprising a polymer and an additive, the fine fiber having a fiber size of about 0.01 to 5 microns a basis weight of 0.0001 to 24 g-m −2 , the substrate layer comprising a filtration media having a basis weight of about 8 to 200 grams/meter 2 ; wherein the fine fiber comprises a layer of the additive on the surface of the fiber; 
 wherein after exposure to air at 140° F. and 100% relative humidity for 16 hours, at least 50% of the fine fiber remains substantially unchanged for filtration purposes. 
 
     
     
       2. The media of  claim 1  wherein the additive is a hydrophobic additive. 
     
     
       3. The media of  claim 1  wherein the coating of additive comprises a protective surface. 
     
     
       4. The media of  claim 1  wherein the additive forms an alloy of the polymer and additive. 
     
     
       5. The media of  claim 1  wherein the layer is about 50 Angstroms in thickness. 
     
     
       6. The media of  claim 1  wherein the polymer comprises a nylon polymer. 
     
     
       7. The media of  claim 6  wherein the nylon is a copolymer comprising repeating residues of nylon 6, nylon 66 and nylon 610 monomer units. 
     
     
       8. The media of  claim 1  wherein the thickness of the fine fiber layer is about 1 to 100 times fiber size. 
     
     
       9. The media of  claim 1  wherein the hydrophobic additive comprises an aromatic resinous composition. 
     
     
       10. The media of  claim 1  wherein the filtration media comprises a cellulosic non-woven. 
     
     
       11. The media of  claim 1  wherein the filtration media comprises a non-woven comprising a synthetic polymeric non-woven. 
     
     
       12. The media of  claim 1  wherein the filtration media comprises a wet laid, spun bond or melt blown non-woven. 
     
     
       13. The media of  claim 1  wherein the fine fiber retains at least 50% of efficiency as measured by ASTM-1215-89, with 0.78 micron monodisperse polystyrene spherical particles, at 20 fpm (6.1 meters/min) in a test bench operating at 20 FPM.